Department of Defense space surveillance and weapons systems require highly accurate inertial knowledge in absolute location and orientation. Current technologies providing these functions are not integrated into a single, light-weight, low-cost, power-efficient, and drift-free instrument. Applied Technology Associates (ATA) proposes to further develop its innovative Auto-correcting Inertial Measurement Unit (ACIMU) to address this technology gap. The ACIMU includes autonomous auto-correcting capabilities to overcome the inherent drift associated with all inertial measurement units (IMUs). The joint inclusion of a global positioning system (GPS) receiver along with a state-of-the-art autonomous star tracker makes available the necessary information required for the auto-correcting capability. To provide high performance inertial sensing in a small package, the innovative blending of ATA magnetohydrodynamic (MHD) rate sensors with high performance MEMS gyros and compact accelerometer triad is proposed. The aiding sensors coupled with the inertial sensors forms the sensor suite of the ACIMU which is then combined with ATA developed fusion algorithms and implemented in radiation hardened electronics. The strap-down design proposed offers reduced power, size, weight, and cost with enhanced functionality/modularity for compatibility with telescope mounting on the MDA space tracking and surveillance system (STSS) satellites.